In a communications network, the transmission of some data packets require meeting some transmission latency constraints, whereas the effective transmission latency is less important for some other data packets.
The former data packets are for instance control packets for the management of the communications network, or data packets related to a real-time application, such as video-streaming. For these data packets, what is important is to meet the latency constraint.
The latter data packets are for instance files contents downloaded from or uploaded to a communication device. For these data packets, what is important is to maximize the throughput, in order to reduce the overall transfer time period from the application standpoint. Said latter data packets are generally referred to as best effort data packets.
Generally, in order to take into account these two aspects, a scheduler device schedules the data packets by first serving the latency-constrained data packets to ensure that the latency constraint is met and by then serving the other data packets with the resources that are remaining.